Invasive Species

What do zebra mussels (Dreissena polymorpha), kudzu (Pueraria lobata), and the European starling (Sturnus vulgaris) all have in common? They’re all invasive species to North America, meaning they came from somewhere else. You’ve probably heard of at least one of these because of their major impact on our environment. For example, on the Eastern Shore of Maryland, there are patches of land that are completely covered by kudzu. Every year when I drive by one of these kudzu clusters, they seem to take over more forest and grasslands. Invasive species beat our native species to food and water and completely change the environment for the worse. They cause a decrease in native species and an increase in erosion. It’s important that we remove invasive species and limit them spreading in our environment before they do more damage.

Ok, so we understand that invasive species are bad, but how did they get here? Usually, they’re released unknowingly. For example, boats carrying zebra mussels on their hulls unintentionally brought them into the Great Lakes. On the other hand, sometimes people bring them in deliberately. Kudzu was introduced by a government-sponsored program to prevent erosion, but as time passed, it became obvious that it worked too well as a ground cover. The European starling was brought into North America for a completely different purpose. It is rumored that they were released in the late 1890’s in an effort to introduce all the birds mentioned in the works of William Shakespeare.

Regardless of how these non-native species got here, we need to take precautions to prevent a further invasion of our neighborhoods and parks. Take some time to become familiar with the native plants and animals in your area.

Learn about what belongs. The more you know about the plants that grow naturally in your neighborhood, the more you can help prevent the spread of non-native species.

Plant native species of plants in your garden.

Never release unwanted pets into the wild; they can wreak havoc on native plants and animals.

While growing populations of species not present in some ad hoc ‘before time’ represent unanticipated change, it’s absurd to cast them as cartoonish villains in an otherwise benign landscape. Zebra mussels, kudzu and starlings have nothing “in common” as organisms other than the deep evolutionary history all plants and animals on the planet seem to share. ‘Alien’ and ‘invasive’ are purely metaphorical categories that appeal to casual (not causal) thinkers, but they don’t capture the essence of our situation—if, indeed, there is a single essence to capture. It’s far from clear what can and should be done in any particular case, especially when a species becomes as established and integral to a regional ecosystem as any of the three mentioned here. One reason it’s far from clear is that we barely understand them individually; when considered together, the picture becomes murkier and more frightening. That is a key point. Lumping introduced species together as a single phenomenon to be opposed is emotionally appealing (therefore politically expedient and even commercially profitable) but it doesn’t begin to address the fact that globalization isn’t limited to human affairs. Efficiencies that internalize benefits while externalizing costs still have costs. Our foresight is limited; unintended outcomes abound. Our transportation technologies are imprecise, scooping up, carrying along and ultimately marooning many organisms of many kinds in many places. It happens somewhere practically every minute of every day. Some of them survive, because that’s what organisms do, if they can. That won’t change anytime soon. Yet another “I deplore them too!” blog post doesn’t help anyone understand the problems involved, much less contribute to solving them.